前兩天又一次要搞微信支付，想想就難過。因為貴公司的文檔真心無力吐槽。前面幾個步驟還好，這里記錄一下調(diào)起支付的相關(guān)代碼。

iOS微信支付文檔地址

集成 實例化 調(diào)用弄完后，翻到了“調(diào)起支付”這里。懵逼了很久。

下面三個方法記錄一下

1.MD5加密算法
2.微信需要的簽名算法(sign)
3.調(diào)起支付方法

// 傳入訂單信息(大部分支付的訂單信息都是服務(wù)端返回的，客戶端生成訂單信息會存在安全問題)
- (void)weixinPayRequestWithOrderString:(NSString *)orderString
{
    time_t now;
    time(&now);
    NSString *time_stamp = [NSString stringWithFormat:@"%ld",now];
    NSString *nonce_str = [self md5:time_stamp];
    NSString *package = @"Sign=WXPay";
    
    NSMutableDictionary *signParams = [NSMutableDictionary dictionary];
    [signParams setObject:APP_ID forKey:@"appid"];
    [signParams setObject:nonce_str forKey:@"noncestr"];
    [signParams setObject:package forKey:@"package"];
    [signParams setObject:MCH_ID forKey:@"partnerid"];
    [signParams setObject:time_stamp forKey:@"timestamp"];
    [signParams setObject:orderString forKey:@"prepayid"];
    
    NSString *sign = [self createMD5Sign:signParams];
    
    PayReq *req = [[PayReq alloc] init];
    req.openID = APP_ID;    //APPID
    req.partnerId = MCH_ID; //商戶號
    req.prepayId = orderString;
    req.nonceStr = nonce_str;
    req.timeStamp = time_stamp.intValue;
    req.package = package;
    req.sign = sign;
    [WXApi sendReq:req];
}

// MD5加密方法
- (NSString *)md5:(NSString *)input
{
    const char *cStr = [input UTF8String];
    unsigned char digest[16];
    CC_MD5(cStr,(CC_LONG)strlen(cStr), digest); // This is the md5 call
    
    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    
    for(int i = 0; i < CC_MD5_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];
    
    return  output;
}

- (NSString *)createMD5Sign:(NSMutableDictionary *)dict
{
    NSMutableString *contentString = [NSMutableString string];
    NSArray *keys = [dict allKeys];
    //按字母順序排序
    NSArray *sortedArray = [keys sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        return [obj1 compare:obj2 options:NSNumericSearch];
    }];
    //拼接字符串
    for (NSString *categoryId in sortedArray) {
        if (![[dict objectForKey:categoryId] isEqualToString:@""] && ![categoryId isEqualToString:@"sign"] && ![categoryId isEqualToString:@"key"]) {
            [contentString appendFormat:@"%@=%@&", categoryId, [dict objectForKey:categoryId]];
        }
    }
    //添加key字段
    [contentString appendFormat:@"key=%@", PARTNER_ID];
    //得到MD5 sign簽名
    NSString *md5Sign = [self md5:contentString];
    return md5Sign;
}